Blocking oscillator



Jan. 15, 1952 G. HEPP 2,582,697

BLOCKING OSCILLATOR Filed April '7, 1948 GFRA PD H EPP IN VEN TOR.

A GENZ Patented Jan. 15, 1952 BLOCKING OSCILLATOR Gerard Hepp,E-indhoven, Netherlands, assignor to Hartford National Bank and TrustCompany, Hartford, Conn, as trustee Application April 7, 1948, SerialNo. 19,455 In the Netherlands April 22, 1947' In knowncircuit-arrangements for producing impulse-like currents or voltages useis made of a discharge tube, with which is inserted between the anodeand grid circuits a back-coupling which is arranged to be such that ananode-current impulse is converted with a given time lag into agrid-voltage impulse, with the result that the anode current of the,tube temporarily passes through the tube in a pulse-like fashion. Insuch circuit-arrangements the value of the invariably positive currentimpulses cannot be adjusted to any desired value and is entirelydetermined by the parameters of the tube, more particularly by thosepoints of the anode-current control-grid voltage characteristic curve ofthe discharge tube which are widely divergent in straight-linerelationship, the term positive impulse being to be understood to meanan impulse at which an anode current passes for a comparatively shorttime and no anode current passes for a comparatively long time.

The invention has for its object-to provide a circuit-arrangement whichpermits of also producing negative impulses and which'in additionreadily permits of adjusting the impulse to any desired value. In thecircuit-arrangement according to the invention, the discharge tube mayin addition accomplish other functions, for example, may be used forproducing a plurality of positive and/or negative impulses or foramplifying or generating electrical oscillations.

According to the invention, pulse-like currents or voltages are set upin the anode circuit of a discharge tube, a pulse-like voltage takenfrom the anode circuit charging, through a rectifier, a condenser whichbecomes discharged, in part, across a resistance and a rectifier withthreshold voltage included in the grid circuit of the discharge tube, insuch manner that the grid Voltage of the discharge tube varies inapulse-like fashion if the condenser is discharged below a valuecorresponding to the said threshold voltage.

In order that the invention may be more clearly understood and readilycarried into effect, it will now be described more fully with referenceto the accompanying drawing.

Referring to Fig. 1, l designates a discharge tube, the anode circuit ofwhich includes a transformer 2, the secondary winding 3 of which isconnected through a rectifier 4 to a condenser 5. Thi condenser 5 isconnected through a resistance 6 and a second secondary winding 9 of thetransformer 2 to the series combination of a rectifier and a thresholdvoltage source B1, which combination is included in the r d ci cu t Oith 5 Claims. (01.250-36) dischargetube I. The pulse-like oscillationsmay be taken, for example, from a terminal ll;

The operation of the tube is explained with reference to Fig. 2, ofwhich the lower half shows the voltage-variation and the right-hand halfshows'the current variation in a ia-Vg anode-current control-gridvoltage characteristic curve.

Assuming that at a certain instant a pulse-like voltage is set up in theanode circuit of the-discharge tube I, the secondary 3 of-thetransformer 2 included in the anode circuit of the tube I will haveinduced init a pulse-like voltage which is rectified by a rectifier 4.For the pass direction of the rectifier 4, which directionis indicatedin Fig. l, the condenser 5 becomes charged to a positive value; thecondenser voltage is denoted by a dotted line at the bottom of Fig. 2.The condenser 5 becomes discharged across-the resistance 6 and therectifier l with threshold voltage B1- and across the leakage resistanceM of the rectifier 4. Since the resistance of the rectifier I isnegligible compared with-the resistance 6, the grid I5 of the tube 1will have a substantially constant potentialB1 a long as the voltageacross the condenser 5 exceeds the voltage of the voltage source B3. Atthe moment when the voltage of condenser 5 falls below the voltage ofthe voltage source B2, the grid voltage of the tube l (full curve at thebottom of- Fig. 2) drops, with the result that the anode current of thistube also drops (full curve on the right-hand side of Fig. 2). This dropof grid voltage of the tube l is accelerated by the feedback winding 9of transformer 2, which winding is connected in series with thecondenser 5 and the resistance 6, so that it assumes a pulse-likepattern, the level of the impulses produced across the grid of the tubeI being determined by the disabling point A of the tube 1.

By providing the rectifier 8 havingv a" threshold voltage B2 it ispossible to ensure that the grid voltage cannot drop below the valueBz,so that this permits of controlling the level of the said impulses.

With these circuit-arrangements it becomes manifest that the nonlinearcharacteristic curve of the discharge tube I need not be utilized, andthis permits of using the latter also for the ac complisment of otherfunctions, such as the production of further positive and/or negativeimpulses or the amplification or production of electrical oscillations.Thus, Fig. 1 shows, for example, a circuit-arrangement in which thistube I also acts as an amplifier of oscillations rendered effective inthe grid-circuit of the discharge sired value.

plified voltage and the produced impulses may be taken from the terminalII. In order to prevent the nonpulse-like oscillations produced across,

the anode circuit of the tube I from unduly controlling the grid [5 ofthe tube I, through the transformer 2 and the winding 9, which, owing tol the conductivity of the rectifier 1 will never be possible as long asthe total voltage produced across the resistance 6 exceeds the voltageof the battery B1, provision is made of impedances 'lzand l3 whichsuppress in the transformer 2 the frequencies of the oscillations fed tothe transformer l0.

' 'I 'l'iecircuit-arrangement above described permits of producingnegative impulses of any de- Reversal of the pass direction of therectifiers 4, 1 and 8 and the polarity of the voltage sources B1 and B2permits of similarly producing positive-impulses.

' What I'claim is:

1 A- circuit arrangement for generating voltagepulses comprising anelectron discharge tube having a cathode, a grid and an anode, an anodecircuit for applying an operating potential tov said anode,- a chargingcondenser, first and second rectifiers, means coupled to said anodecircuit to derive a voltage pulse therefrom and for applying said pulsethrough said first rectifier across 'said'condenser to charge same, animpedance coupled to said anode circuit to derive a positive feedbackvoltage'therefrom, a resistance, a source of direct voltage, means toapply said feedback voltage to said resistance in series with saidsecond rectifier and said source in the order named, a discharge networkconnected across said condenser and including said resistance, saidsecond rectifier and said source in series relation, and means to applythe voltage developed across said second rectifier between said grid andsaid cathode, the polarity of said source being arranged inopposition tothe polarity of charge on said condenser, said source having a magnitudeat which when said charge falls to a predetermined value said tubeproduces said voltage pulses.

2. An arrangement, as set forth in claim 1, further including a thirdrectifier connected in series with a second voltage source across saidsecond rectifier, the directivity of said third rectifier being arrangedin opposition to that of said second rectifier,

3. An arrangement, as set forth in claim 1, further including a circuitforapplying oscillations to said tube to be amplified, said circuitincluding means interposed between said grid and said point to applysaid oscillations to said tube.

4. A circuit arrangement for producing voltage pulses comprising anelectron discharge tube having a cathode, a grid and an anode, atransformer having a primary and first and second secondaries, means toapply a constant potential to said anode through said primary, first andsecond rectifiers, a charging condenser, said first secondary beingconnected to said condenser through said first rectifier, a resistance,a source of direct voltage, said second secondary being connected inseries with said resistance, said second rectifier and said source inthe order named across said condenser, the polarity of said source beingopposed to the polarity of the charge attained by said condenser, andmeans to apply the voltage developed across said second rectifierbetween said grid and said cathode, said source having a value at whichwhen said condenser is discharged to a predetermined level said tubeproduces said pulses, said second secondary being connected to providepositive feedback.

5. A circuit arrangement for producing voltage pulses and amplifyingoscillations comprising an electron discharge tube having a cathode, agrid and an anode, a transformer having a primary and first and secondsecondaries, means to apply a constant potential to said anode throughsaid primary, first and second rectifiers, a charging condenser, saidfirst secondary being connected to said condenser through said firstrectifier, a resistance, a source of direct voltage, said secondsecondary being connected in series with said resistance and said secondrectifier and said source across said condenser, the polarity of saidsource being opposed to the polarity of the charge attained by saidcondenser, said second secondary being arranged to provide positivefeedback, means to apply the voltage across said second rectifierbetween said grid and said cathode, said source having a value at whichwhen said. condenser is discharged to a predetermined level said tubeproduces said pulses, and transformer means for impressing saidoscillations intermediate said grid and said junction of said resistanceand said second rectifier.

GERARD HEPP.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,207,511 Geiger July 9, 19402,250,706 Geiger July 29, 1941

